Nicholas Bastin wrote:
> Generally we try to meet in the middle on __repr__ - in many cases,
> it's most convenient if the output from __repr__ can be fed back into
> a factory or constructor for the class the text came from, so that
> the following expression is legal:
>
> new_object = Microsoft.DirectX.Vector3(repr(old_object))
>
> since
>
> eval(repr(old_object))
>
> usually isn't convenient, fast, or safe.
Consider the output of repr(file('foo', 'rw')).
> Although, lets be clear in this case, I have no idea whether either
> one of those constructions will actually work for the object in
> question (well, clearly the eval() construction won't work). It's
> just that it's much more common to find a __repr__ which makes the
> first construction valid more often than the second. (Obvious,
I'm not aware of any .NET objects that can be constructed by a single string
containing newline-separated variables / value pairs and leave you with
something useful (apart from string and like circumstances, obviously.)
> <Object foo at 0xFFFFFFFF> isn't going to solve anybody's problem
> when it comes to recreating the object).
No, but __repr__ is supposedly for debugging; it's quite difficult to tell the
difference between vector A with X = Y = Z = 0 and vector B with X = Y = Z = 0
with just the current output. There is also the case where ToString returns 2
pages of variable / value pairs. If I want to see variable / value pairs I'm
quite capable of using repr(obj.__dict__).
--
Jonathan
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